Rooted Plantlet Production in a Vegetatively Reproductive Red Clover (\u3ci\u3eTrifolium pratense\u3c/i\u3e L.) cv. Astred

Vegetatively reproductive cultivars of red clover (Trifolium pratense L.) can produce clonal daughter plantlets under certain management and environmental conditions, which may improve sward persistency. Six trials involving spaced plants, pure swards or grazed mixed swards were conducted near Massey University, Palmerston North, New Zealand, from 1995 to 1998. Rooted plantlets counted in autumn of each year ranged from 5.8±1.6 to 43±5.1 rooted plantlets/parent plant for ungrazed spaced plants, and 0 to 1.8 rooted plantlets/parent plant for pure and mixed swards under grazing management. It is concluded that clonal, rooted plantlet production is highly variable in Astred depending on grazing management, environmental conditions and companion species, but offers a feasible replacement mechanism for maintaining red clover persistence in mixed and pure swards

Magnetization of small lead particles

The magnetization of an ensemble of isolated lead grains of sizes ranging from below 6 nm to 1000 nm is measured. A sharp disappearance of Meissner effect with lowering of the grain size is observed for the smaller grains. This is a direct observation by magnetization measurement of the occurrence of a critical particle size for superconductivity, which is consistent with Anderson's criterion.Comment: 7 pages, 5 figures, Submitted to PR

The Potential of Different Forage Combinations for Green-Chop Silage

On the Canterbury Plains of New Zealand (NZ) there is an opportunity on cropping farms, between summer harvest and autumn/winter sowing, to grow forage crops to make high quality silage. Recently, cereal cultivars have been specifically bred for forage production and suitability for whole-crop silage (de Ruiter et al. 2002), and also high legume (e.g. sulla) content forage mixes have resulted in high quality silages with high lactic acid and soluble carbohydrate content (Niezen et al. 1998). This trial aimed to determine the yield potential of various cereal/legume forage mixtures summer sown and harvested for silage in autumn

Supplementing Dairy Cows in Late Lactation With High Quality Silages

Agriculture on the Canterbury Plains of New Zealand is a mixture of integrated cropping and pastoral enterprises. Cropping farmers often provide supplementary feed for dairy farmers by growing forages for high quality silage. Such silages can improve milk production by increasing dry matter (DM) intake and/or by alleviating deficiencies of either soluble carbohydrate or protein in pasture (Woodward et al., 2002). Legumes and/or cereals have potential to make large quantities of high quality silage (de Ruiter et al., 2002). This trial aimed to determine milk production and composition differences between three silages fed during late lactation

Scorpion venom increases acetylcholine release by prolonging the duration of somatic nerve action potentials

Scorpionism is frequently accompanied by a massive release of catecholamines and acetylcholine from peripheral nerves caused by neurotoxic peptides present in these venoms, which have high specificity and affinity for ion channels. Tityus bahiensis is the second most medically important scorpion species in Brazil but, despite this, its venom remains scarcely studied, especially with regard to its pharmacology on the peripheral (somatic and autonomic) nervous system. Here, we evaluated the activity of T. bahiensis venom on somatic neurotransmission using myographic (chick and mouse neuromuscular preparations), electrophysiological (MEPP, EPP, resting membrane potentials, perineural waveforms, compound action potentials) and calcium imaging (on DRG neurons and muscle fibres) techniques. Our results show that the major toxic effects of T. bahiensis venom on neuromuscular function are presynaptically driven by the increase in evoked and spontaneous neurotransmitter release. Low venom concentrations prolong the axonal action potential, leading to a longer depolarization of the nerve terminals that enhances neurotransmitter release and facilitates nerve-evoked muscle contraction. The venom also stimulates the spontaneous release of neurotransmitters, probably through partial neuronal depolarization that allows calcium influx. Higher venom concentrations block the generation of action potentials and resulting muscle twitches. These effects of the venom were reversed by low concentrations of TTX, indicating voltage-gated sodium channels as the primary target of the venom toxins. These results suggest that the major neuromuscular toxicity of T. bahiensis venom is probably mediated mainly by α- and β-toxins interacting with presynaptic TTX-sensitive ion channels on both axons and nerve terminals

How did the Electrical Development Association attempt to mould domestic electricity demand in Britain, 1945-1964?

Demand management in Britain is not new. We suggest that there is value in exploring earlier experiences, for the insights they offer into the culture and practices of the electricity supply industry and into the challenges demand management faces today. The paper focuses on the two decades after the Second World War, in which the UK electricity supply industry tried to mould and shift the time profile of electricity demand, especially for domestic heating. Between 1945 and 1964 the Electrical Development Association (EDA) was an industry actor that worked to impact domestic electricity demand. As the industry’s central public relations arm, its main role was to promote electricity and its use, although in this period it also attempted to reduce domestic demand at peaks, especially for space heating. In the late 1940s, when electricity supply was very tight, it did this by advertising to discourage the use of electric fires. Later, the EDA encouraged the take-up of off-peak appliances, such as night-storage heaters, and considered these promotional activities successful attempts at load-shifting. The EDA is thus an interesting case of demand management by an organisation whose main interest was to increase, not decrease, the use of electricity, a position not unlike that of most large electricity utilities today. The paper explores EDA’s stated reasons for engaging with demand management and the context of their work in this area, including shifting government policies and social changes and competition from other fuels and technologies, in an attempt to understand the viewpoint and actions of one of the industry’s influential but traditional actors. The EDA was constantly negotiating between critical views of its work, from both within and without the electricity industry, and their own organisation’s desires both to promote electricity and shift demand off-peak. These negotiations are shown to have influenced their demand management work. The paper also investigates, partly as a reality-check against EDA’s self-promotion, what types of heating appliances were actually used and preferred by domestic consumers

Neurotoxicity of Tityus bahiensis (brown scorpion) venom in sympathetic vas deferens preparations and neuronal cells

Systemic scorpion envenomation is characterized by massive neurotransmitter release from peripheral nerves mediated primarily by scorpion venoms neurotoxins. Tityus bahiensis is one of the medically most important species in Brazil, but its venom pharmacology, especially regarding to peripheral nervous system, is poorly understood. Here, we evaluated the T. bahiensis venom activity on autonomic (sympathetic) neurotransmission by using a variety of approaches, including vas deferens twitch-tension recordings, electrophysiological measurements (resting membrane potentials, spontaneous excitatory junctional potentials and whole-cell patch-clamp), calcium imaging and histomorphological analysis. Low concentrations of venom (≤ 3 μg/mL) facilitated the electrically stimulated vas deferens contractions without affecting postsynaptic receptors or damaging the smooth muscle cells; transient TTX-sensitive sustained contractions and resting membrane depolarization were mediated mainly by massive spontaneous ATP release. High venom concentrations (≥ 10 μg/mL) blocked the muscle contractions and induced membrane depolarization. In neuronal cells (ND7-23wt), the venom increased the peak sodium current, modified the current-voltage relationship by left-shifting the Nav channel activation curve, thereby facilitating the opening of these channels. The venom also caused a time-dependent increase in neuronal calcium influx. These results indicate that the sympathetic hyperstimulation observed in systemic envenomation is presynaptically driven, probably through the interaction of α- and β-toxins with neuronal sodium channels

Constraints on narrow exotic states from K+p and K0_Lp scattering data

We consider the effect of exotic S=+1 resonances Theta+ and Theta++ on K+p elastic scattering data (total cross section) and the process K0_Lp-->K0_Sp. Data near the observed Theta+(1540) are examined for evidence of additional states. The width limit for a Theta++ state is reconsidered and shown to be much less than 1 MeV.Comment: 4 pages, 3 eps figures; minor corrections, one fig adde

Neurotoxicity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom in vertebrate neuromuscular preparations in vitro and neutralization by antivenom

We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve-muscle preparations in vitro. The venom (0.1-30 µg/ml) showed calcium-dependent PLA2 activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations ≥ 0.3 µg/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 µg/ml) caused neuromuscular blockade in PND preparations within ~ 10 min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 µg/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 µg/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 µg/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom